Abstract: Laboratory testing has become the most direct and accurate method for determining the mechanical properties of rocks. The mineral-rock multiscale analysis technology, using digital core modeling and discrete element simulation, reveals the regulatory mechanism of microscopic mineral mechanical parameters on macroscopic engineering responses, providing a theoretical tool for the assessment and prevention of geological disasters. Nanoindentation is an important technique for studying micromechanics, and current nanoindentation studies on rocks focus mainly on shale and granite; few studies address basalt, gneiss, schist, slate, or other rocks, and little is known about whether the same rock-forming mineral exhibits different micromechanical properties across rocks. In this study, the compositions, contents, apparent morphology and micromechanical properties of the main rock-forming minerals in ten categories of rocks are obtained by means of powder X-ray diffraction test, optical microscope surface observation, electron probe test and nanoindentation test, and the suitable peak loads of different rock-forming minerals for nanoindentation test are selected experimentally. A large body of literature on nanoindentation is compiled to compare the micromechanical properties of the same mineral across rocks and to reveal underlying causes. The indentation results indicate a significant linear relationship between fracture toughness and the elastic modulus; the relationship with hardness is not statistically significant. The appropriate peak load for quartz, potassium feldspar and plagioclase is 7 mN, that for mica is 3 mN, and that for calcite and dolomite is 4 mN. Nanoindentation curves differ substantially among minerals. Quartz data show the least dispersion, followed by potassium feldspar; plagioclase, dolomite, and calcite exhibit moderate dispersion. Compared with published studies, the granite data show strong concordance; for other rocks, the results can guide the selection of nanoindentation parameters. This further provides a basis for parametric modeling of rocks from the perspective of micro-mechanical properties, which is of great significance for studying the micro-macro mechanical behavior of rocks. In addition, in combination with environmental geology and sustainable development needs, multi-scale analysis technology can reveal the mechanical response mechanism of minerals and rocks in complex environments, further expanding its application prospects in the development of new energy materials and ecological restoration engineering.

Key words: rock-forming minerals, mineral components, nanoindentation test, micromechanical properties